Thousands of people are killed in the United States each year by drunk drivers. Many of these people would not have been driving had they realized they had drunk too much. Drunk drivers are having to spend time in jail and pay fines in the range of $1,000 because they did not know they had drunk too much. On the other hand, alcohol in moderation may be good for you. Studies have indicated that a glass of wine a day can increase your lifespan. Cocktail parties are a part of the American way of life. It would be nice if people who drink would not drive, but that is too much to hope for. Very often there is no practical way to get home from a party or the bar except to drive. We need a device to tell us when we have had enough so we can stop or slow down. It should be cheap enough so one could be in every bar and every home where liquor is served. It should be easy to operate, so moderately intoxicated people could operate it and understand the results. Devices exist for estimating blood alcohol level from urine samples, breath samples and blood samples. These devices are too expensive for universal use. Charts exist which can be used to estimate blood alcohol level. These charts are free but they are not doing the job. Why, I do not know. Maybe people don't believe them. Maybe many people can't understand the charts.